Electron tube with luminescent shield, especially tuning tube



April 22, 1952 w. JACOB] ETAL 2,594,025

ELECTRON TUBE WITH LUMINESCENT SHIELD, ESPECIALLY TUNING TUBE Filed Oct. 5, 1950 4 Sheets-Sheet l Fig.3

April 22, 1952 w. JACOB] ETAL I 2,594,025

ELECTRON TUBE WITH LUMINESCENT SHIELD, ESPECIALLY TUNING TUBE Filed Oct. 5, 1950 4 Sheets-Sheet 2 Fig.5

Fig. 5

[I I El fizyevfor Werzzer J c'o aVerwam JV 2262532137:

April 22, 1952- w. JACOBI ETAL 2,594,025

ELECTRQN TUBE WI TH LUMINESCENT SHIELD, ESPECIALLY TUNING TUBE Filed Oct. 3, 1950 4 Sheets-Sheet 3 Fig. i Fig. 9 2L- g \w F/'g.11 Fig. 1;

Fig. 13 V April 22, 1952 w. JACOB] ETAL 2,594,025

ELECTRON TUBE WITH LUMINESCENT SHIELD, ESPECIALLY TUNING TUBE Filed 001;. 3. 1950 4 Sheets-Sheet 4 Patented Apr. 22, 1952 UNITED STATES PATENT OFFICE ELECTRON TUBE WITH LUMINESCENT SHIELD, ESPECIALLY TUNING TUBE Germany Application October 3, 1950, Serial No. 188,161

In Germany September 9, 1949 9 Claims. 1

This invention is concerned with an electron discharge device, especially with a tuning tube having an elongated fluorescent anode which becomes luminous to display, for indicating purposes, a bright and sharply defined luminous, variable light pattern responsive to variations lengthwise of the cathode of the electron flow to the fluorescent anode by varying voltages applied to an associated control electrode.

The object of the invention is to provide, in a discharge device of the above noted specific type, a novel control electrode which is made in the form of a shutterlike member to regulate the flow of electrons emitted by the cathode, so as to cause the fluorescent anode to display the luminous indicating light pattern. The shutterlike control electrode may be a sheetlike member in which is formed a wedge-shaped or trapezoidal opening, and such member may be disposed in parallel with the cathode, or it may be disposed at an angle thereto, so that its spacing from the cathode and from the fluorescent anode varies from point to point lengthwise of the cathode in planes along imaginary lines drawn from the cathode to the fluorescent anode. The control electrode may also be 'made in the form of a frame defining an opening, and may in such case be so constructed and arranged that parts thereof extend in parallel with the cathode and other parts at an angle thereto.

The novel control electrode offers several significant advantages. It is structurally exceedingly simple, and may therefore be produced at less cost than prior electrodes made for the indicated purpose. the new control electrode facilitates assembly with other parts to form the discharge device, thus contributing to further reduction of the production costs. The new control electrode is also more sensitive in operation than control electrodes made heretofore for the purpose in view, and produces very favorable, sharply outlined indication with clearly defined margins between the relatively bright and relatively dark regions.

A predetermined indication, e. g., practically any desired indicatin characteristics may be obtained by properly forming the opening of the shutterlike electrode. The opening should be formed in accordance with a predetermined curve, particularly when it is desired to obtain non-linear indicating characteristics. This object may also be realized by disposing the shutterlike control electrode at an angle to the cathode and the fluorescent anode instead or in The structural simplicity of parallel therewith. The control electrode is, in such angular position effective in a definite plane extending over a. certain depth. The positioning in depth offers advantages even if no particular indicating characteristics are desired. For example, with proper angular positioning, the shutterlike control electrode may be formed simply with an approximately rectangular slot instead of with a wedge shaped or trapezoidal cutout.

It is also possible to employ in place of the angular positionin of the control electrode a corresponding angular positioning of the cathode or of the fluorescent indicating anode. For example, the control electrode may be placed in parallel with one of the electrodes of the discharge device and another electrode may be positioned in an angular plane. It is further possible to arrange all three electrodes (cathode, control electrode and fluorescent indicating anode) in predetermined angular positions relative to each other. The shutterlike control electrode may be made convex or ofconcave shape.

The invention also contemplates the use of a control electrode having a plurality of shutter portions in which are formed trapezoidal or rectangular openings at different side or depth angles and especially at oppositely directed angles. The luminous indication of the fluorescent indicating anode proceeds in such structure from two spots, leavin a certain portion, e. g., the central portion dark or proceeding from the center and causing the luminous effect to extend toward opposite ends.

In order to improve the observation of the luminous indication, it will be in many cases desirable to reduce the dimensions of the outer regions of the control electrode. It is particularly the borders of the edges of the control electrode that-must be considered. The surrounding areasof these edges are to some extent efiective in controlling the flow of the electronswhile the portions-whichare more distant from the opening are either ineffective or contribute very little to the control thereof. It is therefore in many cases possible to reduce the outer areas of the control electrode considerably and to keep them in some cases so small that the structure resemblesaframe.

The objects and features outlined above and additional objects and features of the invention will appear from the detailed description of some embodiments which will presently be rendered with reference to the accompanying drawings. In these drawings,

Fig. 1 shows in schematic perspective an exploded view of a simple embodiment of the invention comprising a control electrode in which is formed a Wedge-shaped opening, the electrode being disposed between the cathode and the fluorescent anode and in parallel therewith;

Fig. 2 shows in like schematic manner an embodiment in which the control electrode is .disposed between the cathode and the fluorescent anode and at an angle thereto;

Fig. 3 illustrates an embodiment comprising an arcuately curved control electrode in which is formed a rectangular slot;

Fig. 4 represents an embodiment in which the control electrode is again a sheetlike member in which are formed two openings;

Fig. 5 shows another embodiment in which .the

control electrode is provided with two wedge shaped cutouts;

Figs. 6 and 7 indicate modified arrangements employing framelike control shutters;

Fig. 8 shows in diagrammatic sectional view an arrangement similar to the one of Fig. 6 or 7. and Fig. 9 illustrates a modification thereof;

Figs. 10 and 11 represent a structure employing a control electrode having a rectangular slot of varying depth;

Figs. 12, 13 and 14 indicate modifications of the structures of Figs. 10 and 11; and

Fig. 15 illustrates a modified control electrode in which only certain marginal zones are eifective.

Referring now to Fig. l, numeral l designates the cathode which is constructed as a tubular cathode carrying an outer emission layer and containing the usual heatingmeans. The sheetlike member 3 having a V-shaped cutout formed therein, as shown, constitutes the control electrode. Between the sheetlike anode members 4 and 5 is disposed the fluorescent anode comprising the rodlike support 1 which is made of glass. This glass rod is provided with a groove 8 facing the cathode, the groove containing the fluorescent substance indicated by numeral 6. The wedge shaped opening in the electrode 3 varies from point to point and thereby causes a variable luminous response of the fluorescent anodes 6-1-8 so that variable portions of the fluorescent substance become activated depending on the control voltages applied to vary the flow of the electrons. The construction of the fluorescent anode is disclosed in copending application Ser. No. 188,162.

The control electrode 9 of Fig. 2 is disposed in angular position between the cathode Ill and the fluorescent anode II which may in this embodiment be a striplike member. This type of anode is likewise disclosed in the copending application Ser. No. 188,162. A particular indication characteristic may be obtained in this case, which could otherwise be produced only by means of an opening formed in accordance with a particular curve. It is possible to produce in this manner a nonlinear characteristic with a control electrode having an opening with straight lateral marginal edges.

The angular positioning of the control electrode also permits deviation from the wedge or trapezoidal form of the cutout and to provide a generally rectangular slot, as shown in the electrode M of the embodiment illustrated diagrammatically in Fig. 3. The cathode l2 and the striplike fluorescent indicating anode l3 are again disposed in parallel relationship. The control electrode 14 is arcuately curved as shown for the purpose of obtaining a desired. and especially a fluorescent anode and to dispose the corresponding remaining third electrode angularly and, as mentioned before, it is finally possible to position all three electrodes angularly relative to one another;

A portion of the elongated fluorescent column or" the indicating anode will be activated in operation while other portions will remain dark. If the indicating tube is used in conjunction with awireless receiver, the border line between the dark and the bright portions of the luminous indicating column will shift incident to the tuning. Reception from a more powerful transmitter will cause greater shifting, thus permitting conclusions as to the energy of the transmitter which may have been tuned in. The indication may be accomplished in two different ways. First, the width of the bright spot may be permitted to grow incident to tuning involving a stronger transmission source and, second, the reverse procedure may be employed, permitting the dark field to grow during the tuning. The second procedure is for many cases more favorable and has in addition advantages from the circuit design point of VIEW.

Such a case is illustrated in Fig. 4. Numeral IS in this figure indicates a cathode which is directly or indirectly heated and which consists essentially of an elongated filament. In back of the control electrode I6 is disposed the narrow, elongated fluorescent indicating anode IT. The control electrode I6 is provided with a wedgelike opening l8 which extends almost thruout its entire length. A circular opening I9 is provided underneath the wedgelike opening i8 having a diameter which corresponds to the widest portion thereof. The openings are so related to given control voltages that a bright luminous spot will be produced by the opening l9 upon the luminous indicating anode ll, independent of the regulation. The wedge shaped opening I8 operates similarly, so that a bright luminous spot also appears at the opposite end of the indicating anode ll which corresponds to the opening l8 at its wide end. In de-tuned condition, the entire indicating anode [1 will be activated. Upon approaching exact tuning, the luminous portion will retreat from the center upwardly, depending on the strength of the received high frequency amplitude, so that the dark field between the upper and lower light spots will steadily grow. It is a fact borne out by experience that bright areas are more impressive to the eye than dark ones. The indication therefore Will become more effective if a longitudinally variably dark area'is disposed between two bright light spots.

The cathode I5 is in this embodiment supplied with direct current which may be tapped from the anode voltage source of a wireless receiver. The filament is poled so that the negative pole is at the upper and positive pole at its lower end. This results in a supporting action with respect to the indication, which may be further increased by conducting the anode current of the tube stage which is to be tuned either wholly or preponderantly over the filament. The anode current drops upon reaching exact tuning and thus reduces the heating current so that the dark field becomes greater.

The observation of the luminous column can be carried out in different ways. In the embodiment shown in Fig. 1, the luminous indicating column is upon a glass rod, i. e., upon a transparent-support T which permits observation from the rear of the device, i. e., looking in a direc tion through the transparent support. In the embodiments shown in Figs. 2 and 3, the control electrodes H and I3 are disposed at an angle and the luminous column may thus be observed from the side. The embodiment Fig. 4 employs a cathode formed by a thin filament which is so thin that it does not noticeably disturh the observation of the luminous column from the front although lying within the field of observation. The control electrode has in this case also part of the'additional function of optically focussing the production of the luminous indication on the indicating anode.

In the form of the invention shown in Fig. 5, the control electrode 22 disposed between the cathode 28 and the indicating anode 2| is provided with two identical wedge shaped openings 23 and 2d. The apices of these openings meet substantially centrally as shown. The cathode 2a may again be poled so as to obtain a supporting eiiect for the indicating action. The center of the heating filament is for this purpose separately tapped and connected with the positive pole of the current source while the upper and lower ends thereof are connected'with the negative pole thereof.

As already mentioned before, it will be in many cases desirable to reduce the area covered by the control electrode and to form it under certain circumstances in the shape of a frame. Such a structure is employed, for example, in the embodiment shown in Fig. 6, the framelike control electrode being indicated at 25. The figure shows a frontal elevational view, 1. e., looking at and past the cathode 28 through the opening in the framelike control electrode 25 toward the indicating anode 21. The frame 25 is made of wire and forms a wedgeshaped or trapezoidal opening. The structure produces a double indicating system comprising two symmetrically disposed parts.

Fig. '7 indicates a simplified form of the embodiment shown in Fig. 6. The control electrode 30 which is a shaped wire is disposed between the thread-like cathode filament 28 and the indicating anode 29. The control electrode may in its simplest embodiment be formed of a single wire which is bent in the shape of the numeral 3. Depending on the magnitude of the control voltage, more or less pronounced light spots 3i and 32 will be produced, resulting in dark areas 33 and 34 of correspondingly varying sizes. The areas 35 and 36 on the indicating anode 2!] become only faintly luminous and thereby contribute toward making the indica tion readily apparent.

Fig. 8 illustrates in sectional view an arrangement of the type discussed with reference to Figs. 6 and 7. Between the cathode 31 (cathodes 26 and 28, respectively, of Figs. 6 and '7) and the indicating anode 38 (anodes 21 and 29, respectively, of Figs. 6 and 7) are shown portions of the control electrode 39 corresponding to the control electrodes 25 and 30, respectively, of Figs. 6 and '7. Fig. 8 also shows auxiliary electrodes 40 and i! disposed alongside the control electrode 39. These auxiliary electrodes serve as screening electrodes and may be connected to a fixed potential, i. e'., to the cathode potential.

The arrangement according to Fig. 9 is a medi fication of the one indicated in Fig. 8. In this case, the. screening electrodes t2 and 43 are not .disposed'in the same plane as the control electrode 44 but are carried arcuately forward with respect thereto. The indicating anode 25 is similarly curved. Numeral 36 indicates the cathode.

As mentioned previously, the edges of the shutterlike control electrode may be formed in such a manner that they extend thruout their length. with varying depth relative to the associated indicatinganode. The opening in such control electrode may be a rectangular slot which varies in depth, from point to point lengthwise of the cathode and the indicating anode. An example of such an embodiment is shown in-,-Fig. 1c. i'fis. disposed the control electrode 48 having a rectangularopening; and in back thereof is the indicating anode 49. The arrows 59 indicate the direction in which the lubinous indication is observed along lines passing on either side of the cathode 47 thru the slotlike opening in the control electrode 48. The latter is formed with walls of varying thickness, as is apparent from the view illustrated in Fig. 11.

I Fig. 12 indicates a'longitudinal section thru a somewhat modified control electrode of this type, comprising a plurality of leaves 51 which are assembled together.

, .The control electrode shown in perspective view in Fig. 13 is made of sheet stock 52 forming a rectangular slot. Ears 53, 54 are disposed at the sides of the slot and extend therefrom. These ears have a form which corresponds to the structures shown in Figs. 10-12.

If the areas of the control electrode shown in Fig. 13 surrounding the rectangular opening are progressively reduced, the result will finally be a framelike shutter comprising merely the walls corresponding to the ears 53 and 54 of Fig. 13. Such a structure is apparent from Fig. 14. In the direction of viewing, there are disposed, successively, the thin threadlike cathode 55, the control electrode 56, and the indicating anode 51. The inner angular edges 58, 59, B0 and GI form acute angles with the frontal edges 62, 63.

Fig. 15 shows another type of control electrode in which only the lower edges 64, 65, 66, 61 are essentially effective. These edges form an acute angle with an imaginary plane along which takes place the control of the entire electron flow. The structure again produces two bright luminous spots at the ends of the indicating anode. Depending on the magnitude of the control voltages, the extent cf these bright spots will increase or decrease toward the center. The frame may be provided with rounded ends as indicated in Fig 14 at 68, $9, or may be formed angularly as indicated in Fig. 15 at It, ll, respectively.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent of the United States.

We claim:

1. In an electron discharge device having an elongated cathode and an elongated fluorescent indicating anode which becomes luminous to display a light pattern responsive to variations lengthwise of the cathode, of the electron flow from the cathode to the fluorescent anode, caused by varying voltages applied to said discharge device, a control electrode to which said voltage variations are applied for controlling said In back of the threadlike cathode electron flow, said control electrode consisting of an elongated shutterlike member disposed between said cathode and said fluorescent indicating anode and extending solely therebetween, an elongated opening being formed in said shutterlike member through which the electron flow can pass from said'cathode to said indicating anode, predetermined edges of the body of said shutterlike member extending angularly so as to provide for variable electron flow control longitudinally thereof.

2. The structure defined in claim 1, wherein the edges of said shutter member which form the elongated opening therein extend angularly in transverse direction to form an opening of varying width therein. 3. The structure defined in claim 1, wherein edges of the body of said shutter member extend angularly in depth in planes extending along imaginary lines drawn from the cathode to said elongated fluorescent indicating anode.

4. The structure defined in claim 1, wherein said elongated opening is wedge-shaped.

51' The structure defined in claim l wherein said elongated opening is generally rectangular.

6. The structure defined in claim 1, wherein at least part of the opening formed in said shutterlike member extends in a plane which is disposed at an angle to the plane of at least one of the other electrodes.

7. The structure defined in claim 1, wherein at least part of the body of said shutterlike member is generally arcuately curved in a direction extending alon imaginary lines drawn from the cathode to said elongated fluorescent indicating anode.

8. The structure defined in claim 1, wherein the body of said shutterlike member is made in the form of a frame having narrow portions which define said opening marginally thereof.

9. The structure defined in claim 1, wherein the luminous light pattern produced on said elongated fluorescent indicating anode comprises two distinct areas at the opposite ends thereof which diifer in .relative brightness from the area extending therebetween.

.WERNER JACOBI.

HERMANN HINDERER. HELMUT KATZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

